1. Field of the Invention
This invention relates generally to irrigation sprinklers or sprayheads, and more particularly relates to a telescoping pop-up sprinkler assembly for extending the height of a sprinkler.
2. General Background and State of the Art
An advantage of a pop-up sprinkler over a permanently upright sprinkler extending above the ground is that the entire sprinkler remains buried in the ground until the pop-up sprinkler is activated by water pressure, when the piston is pushed above ground level to spray water. By remaining buried in the ground until activated, damage to the sprinkler can be prevented or minimized that might otherwise occur if the sprinkler were permanently in an upright position above ground level.
Pop-up irrigation sprinklers are commonly manufactured in heights from two to twelve inches. Such pop-up sprinklers usually include a cap, a seal, a piston, a spring, a ratchet and a body. The body is usually longer than the height of the pop-up sprinkler, to allow sufficient space in the body for the spring, seal and end of the piston. For example, a two inch pop body would be four inches long, to allow two inches of piston extension, leaving two inches of piston in the body to support the piston from a side thrust when a half spray nozzle is used, and leaving space for the spring in the compression stage. As heights change in order to achieve adequate spray patterns over taller grasses or shrubbery, tall sprinklers are used. Usually the piston length increases in direct relation the increase in the length of the body of the sprinkler. With a six inch pop-up sprinkler, the sprinkler body is typically about nine inches long, to account for the additional leverage created by the increased height of the pop-up piston. In a twelve pop-up sprinkler, the sprinkler body is typically about fifteen inches long.
It should be readily apparent that for installation of a pop-up sprinkler the hole or trench that has to be dug would need to exceed the total length of the body of the pop-up sprinkler, as well as the height of the connector used to attach the body of the pop-up sprinkler to a water supply pipe, plus the diameter of the water supply pipe. For example, for installation of a two inch pop-up sprinkler, a trench would need to be a minimum of six inches deep if not up to ten inches deep, and for installation of a twelve inch pop-up sprinkler, the trench may be up to eighteen inches or twenty-four inches deep.
It would be desirable to provide a pop-up sprinkler that telescopes to extend the height of the sprinkler, to reduce the depth of trenches needed for installation of the pop-up sprinkler, and to minimize installation time and expense. It would also be desirable to provide a pop-up sprinkler with improved seals for the telescoping piston assembly. The present invention satisfies these and other needs.